Arrangement in compressed air circuit breakers



Nov. 28, 1950 H. FORWALD 2,531,617

ARRANGEMENT IN COMPRESSED AIR CIRCUIT BREAKERS Filed Jan. 1'7, 1948 Wye/1 for fiaa/ro/v Fbrh/a/a/ w /q z ornex Patented Nov. 28, 1950 ARRANGEMENT IN COMPRESSED AIR CIRCUIT BREAKERS Haakon Forwa-ld, Valhalla, Ludvika, Sweden, assignor to Allmanna Svenska Elektriska Aktiebolaget, Vasieras, Sweden, a Swedish corporation Application January 17, 1948, Serial No. 2,914 In Sweden March 24, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires March 24, 1963 2 Claims.

The present invention has for its object to provide a compressed air circuit breaker with a plurality of series connected contact pairs in which the blow-out opening of a contact pair is closed by a valve when the movable contact of a consecutive contact pair has terminated its opening stroke. The main feature of the invention is that the said blow-out opening valves as well as the movable contacts are operated by compressed air delivered from an operating valve separate from the valve controlling the delivery of extinguishing air to the breaker. Another feature of the invention is that the operating air for the said blow-out opening valves is controlled by the motion of the movable contacts, so that the said valves are closed after the movable contacts have terminated their motion.

It has heretofore been proposed to operate the movable contacts as well as the said valves by the are extinguishing air. This arrangement, how ever, has the disadvantage that the contacts may be opened before the extinguishing air in the breakers has reached a sufficient pressure, and as the motion of said valves is dependent upon the motion of the movable contacts, said valves may become closed before the arcs have been extinguished.

In accordance with the present invention, this disadvantage is avoided, since the movable contacts and the valves are operated by air from a separate operating valve.

The invention is illustrated on the accompanying drawing, where I designates the bottom plate of the circuit breaker, 2 a compressed air container, 3 an extinguishing air valve and 4 an operating air valve. The circuit breaker rests on an insulating cylinder 5, which is arranged on the bottom plate I of the circuit breaker, and 6 is an insulator carrying the stationary contact of the disconnecting switch. 1 is the contact arm of the disconnecting switch, which is operated by the insulating shaft 8. On the insulating cylinder a series of insulating cylinders 9 are arranged, which cylinders 9 are connected with the insulator 5 and with each other by means of connecting pieces H) of metal. The stationary contacts H are formed as sleeve contacts, and the movable contacts are designated l2. These contacts l2 are, by means of rods [3, connected with operating pistons M, which move in operating cylinders IS. The blow-out openings for the contact pairs are designated by [6 and are formed in the stationary contacts. The escape of air from the contact are operated by valve operating pistons l8 movable in valve operating cylinders l9.

In operation, at the opening of the circuit breaker, the extinguishing valve 3 and the operating valve 4 are opened, the valve 3 being opened a little before the valve 4, so that the whole circuit breaker becomes filled with compressed air before the contacts separate. When the valve 4 is then opened, air flows up through the operating pipe line 253 to the upper sides of the contact operating pistons I4, and the movable contacts I2 then moving downwards. When the pistons l4 have reached their lower position, a passage 2| between the upper cylinder I5 and the lower cylinder I9 is opened, so that the operating air can also reach the upper side of the lower piston l8. When this piston l8 has commenced its motion, a direct passage Zi from the pipe line 20 to the upper part of the lower cylinder 19 is opened. When closing the breaker, the operating valve 4 is closed, and the contact pistons l4 and valve pistons I8 move back to their original positions, being actuated by springs.

For the operating cylinder of the lowermost breaking gaps, an operating passage such as 2| is of course not necessary, and for the closing arrangement of the uppermost blow-out opening, a damping of the motion of the piston 18 must be taken care of, so that the blow-out opening of this breaking gap is not closed before the movable contact has reached its end position.

I claim as my invention:

1. A compressed air circuit breaker with series connected contact pairs, comprising movable contacts and stationary contacts, a blow-out opening for each contact pair, an extinguishing air valve for the delivery of extinguishing air to said contact pairs, contact operating cylinders, operating pistons movable in said operating cylinders for operating said movable contacts, a separate pipe line directly connecting said operating cylinders with a compressed air container, an operating valve in said pipe line, a valve member for each contact pair for closing the blow-out opening from a consecutive contact pair, an operating piston for each of said valve members, a valve operating cylinder for each of said valve operating pistons, and means giving the contact operating air access to each of said valve operating cylinders, when said 0 contact operating piston in a preceding contact pair has terminated its opening stroke.

2. A compressed air circuit breaker with series connected contact pairs, comprising movable contacts and stationary contacts, a blow-out opening pairs is controlled by valve members I1, which for each contact pair, an extinguishing air valve ating valve in said pipe line, a valve member for.

each contact pair for closin a, blow-out opening. from a consecutive contact pair, an operating piston for each of said valvemembers, acylinder for each of said valve operating pistons, a passage from the said contact operating cylinder of one contact pair to the valve operating cylinder of a consecutive contact pair, giving the operat ing air access to the upper side of said valve 15 2,331

operating piston when said contact operating piston in. a preceding contactpair has terminated its openingstroke, and a passage from the said operating air pipe line to the valve operating cylinder opened by the valve operating piston at the. commencement of its motion.

HAAKON FORWALD.

REFERENCES CITED The following references are of record in the file of this patent:

n rap STATES PATENTS Name Date Thommen Oct. 12, 1943 Number 

